The development of improved ice confections in particulate form is of considerable commercial interest. Frozen ice confections comprising flavoured ice granules, for example, which are both refreshing to the consumer and have an aesthetically pleasing appearance, are particularly desirable and are commercially available.
A disadvantage associated with ice confections containing ice granules is that, on frozen storage, the individual granules tend to stick or clump together, forming a hardened product. Not only does this adversely affect the eating sensation experienced by the consumer but it also has a detrimental effect on the industrial processability of the product as the resulting clumped product can be difficult to handle, particularly with regard to portioning or dosing.
Various approaches to the problem of overcoming the effects of clumping in frozen particulate ice products have been proposed in the art. These may be conveniently be divided into methods for dealing with the clumping once it has occurred and methods for preventing clumping occurring in the first place.
Warming up the product from the frozen storage temperature to a higher temperature for a period of time can help to make the product more free flowing but this is generally undesirable where the product is intended for consumption from frozen as the changes in temperature can lead to problems with microbiological contamination.
Alternatively, by controlling the temperature at which the ice granules in the frozen confection are prepared, it has been found that the problem of the granules adhering to each other can be reduced. U.S. Pat. No. 5,126,156, for example, describes a method for preparing a free-flowing, frozen dairy product in which beads of product are prepared by dripping the formulation into a freezing chamber and are then stored at a temperature between −30° F. and −40° F. (−34° C. to −40° C.). In U.S. Pat. No.5,698,247, it is disclosed that if the temperature is maintained at −10° C. or below during the manufacturing process (and furthermore if the granules are manufactured to be approximately spherical in shape) then ice granules in a water-ice product can be prevented from sticking together.
Coating of individual ice granules with a coating suitable for consumption (such as a fat, a mixture of fats and mono- and/or diglycerides or fibrous products such as carbohydrate polymers and natural polysaccharides) in order to give improved processability is described in EP-A-1 075 794.
An alternative approach is described in U.S. Pat. No. 4,310,559. Here, adhesion of ice granules resulting from melting of the surface as the ice blocks are crushed to produce the granules may be prevented by contacting the granules with a refrigerant for an extremely short period of time prior to sifting.
The existing approaches to overcoming the problem of ice granule clumping require complicated additional process steps or sophisticated process controls, leading to increased costs. Techniques involving coating the surface of the granules can have adverse effects on the final product eating quality. There remains therefore a continuing need for an improved method for the preparation of free flowing frozen ice confections comprising ice granules.
Tests and Definitions
Particle Size
Metal sieves in the range 0 to 9.5 mm were used to measure the frozen particle size. The sieves were placed together in sequence (smallest to highest) to form a tower and cooled to −25° C. A sample of frozen particles (100-200 g) is placed on the top sieve (9.5 mm). The stack of sieves was shaken for 1 minute to ensure good separation. Each sieve was then weighed and the % weight of frozen particles in each size class was calculated.
Total Solids
A known weight of liquid material is placed on the heat balance. The sample is heated until there is no change in mass and the % TS calculated.